The following work is proposed: To continue upgrading and improving the standard methods of producing zoospores of Lagenidium giganteum from liquid cultures to simple and economical media. Investigations into the properties of zoospores will be done relating to shelf and refrigerator life, temperature, virulence effect of ions and similar substances. To develop the new Louisiana strain and to study similar properties. To determine whether the fungus overwinters and to repeat controlled experiments in ponds and drums which have sentinel mosquito larvae. To test water depths in ponds and drums for infectivity and to monitor the survival of the fungus in ponds and drums throughout an entire mosquito breeding season (March - October), beginning with either an overwintering survival (if that occurs) or with an early spring inoculation. To compare where appropriate the responses of the Louisiana strain of L. giganteum to the goals outlined above.